Kiln for calcining stone



(No Model.) 2 SheetsSheet l.

G. E. GARLETON.

KILN FOR GALCINING sTONE, 8x0.

Patented Mar. 12, 1889.

(No Model.)

2 Sheets-Sheet 2. G. E. OARLETON.

KILN FOR GALGINING STONE, &c.

No. 399,495. Patented Mar. 12, 1889.

N PETERS. PhnI0-Lhhographcn wnhingtun. D. C.

NITED STATES PATENT OFFICE.

GRANVILLE E. CAR-IJETON, OF ROCKPORT, MAINE.

KILN FOR CALCINING STONE, 84,0.

SPECIFICATION forming part of Letters Patent No. 399,495, dated March 12, 1889.

Application filed July 7, 1888. Serial No. 279,809. (No model.)

To ((ZZ whom it In/cry concern.-

Be it known that I, GRANVILLE E. (Amin- TON, of Rockport, in the county of Knox and State of Maine, have invented a new and useful Improvement in Kilns; and I do hereby declare that the following is a full, clear, and exact; description of the same.

My invention is an improvement in kilns for calr'i'ining stone in the manufacture of lime or cement.

The main object of the invention is to produce a more perfect draft and more thorough COIDlJllStlOll of the fuel and uniform and 00111- plete diffusion of the heat throughout the barrel of the kiln without any undue heat in any part, whereby the barrel or the arches would be injured.

I have hereinaft er described, in connection with the apparatus, the method of burning the fuel, but do not herein claim the method, as that is the subject of the application tiled in the United States Patent ()ftiee of even date herewith, Serial No. 270,3l0.

The invention is desi ned chiefly forusing coal as a fuel, but may be used either with wood or with a mixture of wood and coal.

The use of coal as a fuel in kilns for calcining li meston c has heretofore been attended with difficulty in respect to the draft, and also in respect to its action upon the stone. In my experiments with this kind of fuel I have applied a blast underneath the grate with good effect; but while this increased the 1 draft it caused the heat to act unevenly upon T the stone in the barrel of the kiln, and by overheat in some parts may unduly injure the arches and kiln. l'pon furthcrexperiment I diseovt-wed that this difliculty attend ing the use of the alr blast under the grate might be overcome by the simultaneous application of a spray' of water or jet of steam applied in front of or over the bed of coal in the filGCllZll'lllJtl'. I have also discovered that a blast of air might be used advantageously in the fire-chamber in connection with a blast of air underneath when the coal is stirred or when fresh coal is added, the air applied above the fire-bed serving to supply oxygen to the unconsumed products of combustion which otherwise would not; be consumed in their passage through the mass of stone in the barrel of the kiln.

the kiln, and I?) the arches.

My invmition consists, as set forth in the following specification, of an apparatus designed to carry out the processes above explained.

In the accmnpanying drawings, which illusirate this in vcntion, Figure 1 shows a vertical section taken through the center of the arches and through the barrel of the kiln. Fig. 2 shows a horizontal section of the kiln on line r .1 of Fig. '1. Fig. 3 shows a view of the arch; Fig. -l, a view of the opening of the arch from the inside of the barrel. Fig. 5 shows a perspective view of the kiln, and Fig. 6 a section of the nozzle for supplying the water or steam-jet.

In the drawings, A represents the barrel of The general construction and arrangement of these arches in their relation to the barrel in. the kiln are the same as those in ordinary use; but for the better operation of my invention I have changed somewhat the proportions of the parts, and although I do not limit myself to the exact proportions I have hereinafter given them. in order that; those skilled in the art may be able better to practice. my invention.

I have represented the barrel of the kiln as having a rear and cross section of five by seven feet. The height of this kiln is the same as those in ordinary use (about thirtytwo feet) having the same cross-section. The kiln mpresented is what is ordinarily called the four-arch kiln, there being four arches, two on each side opening into the barrel of the kiln. Each of these arches is about thirty inches in width and twenty inches in height, it being designed for coal, and therefore requiring only about two-thirds of the height requiret'l in an arch used for burning wood. The pillar used for supporting the arch at: the opening into the barrel is represented at I). The openings (1 on each side of this pillar are ten inches wide and eighteen inches high, the fire-bridge, about two inches in height, as shown at 0, being placed across the openings. The grate shown in the plan view of the arch extends from side to side, and is about twenty by thirty inches in surface area. As shown in the figure representing the front of the arch l the door thereof is somewhat contracted.

The lines E E represent the floor of the IOO arch used for wood, and the lines F F show the height of the floor used for coal. The front opening of the arch constructed for coal is represented by the lines f f, and is sixteen inches in width by about eighteen inches in height. The upper partof this opening is half covered by a plate which extends down to the dotted lines 9 g. Under the grate is the ordinary ash-pit, H, which is closed, and into it is led an air-pipe, h, from any suitable airforcing engine. This is provided with a valve, 1, by means of which the blast may be regulated or altogether excluded. A branchof the main air-pipe is applied to the ash-pit of each arch. A pipe, K, is led across the face of the kiln just above the door, with a branch pipe, 70, leading down into the mouth of the kiln, preferably constructed so as to be swung up out of the way whenever it may be desired to do so, a coupling being provided, as at m, to allow this. This pipe K is connected to any suitable source of supply of water or steam. I prefer to use water, as this is more convenient and serves the same purpose. I find it convenient to use the form shown in Figs. 5 and (i, in which 1; represents a crosssection of the pipe-nozzle with a hole at Z on the side toward the fire. This hole maybe closed or regulated by means of the screwplug L. A plate, M, is arranged, preferably, in horizontal position, so that the stream of water from the hole in the pipe strikes an inclination of the plate and is sprayed toward the coal and upon its surface, where it is immediately converted into steam and in part decomposed by the union of the oxygen with the incandescent coal.

The application of the water or steam .in connection with the air blast I find gives ample draft and volume of products of combustion of the proper temperature, so that the stone in the barrel of the kiln is heated uniformly throughout, so as to be uniformly and rapidly calcined without undue injury either to the arches or to the walls of the kiln. It will. be understood that the steam or the water pipes are provided with valves, by means of which this may be regulated or cut-off.

It is well understood that when the fresh supply of coal is added to the fire, or when the coal is stirred in the arch, large volumes of carbon in finely-divided state, or of carbonic oxide, are disengaged, which escape and pass through the stone in the barrel of the kiln unconsumed. In order to provide for the consumption of this carbon and carbonic oxide, 1 provide an air-pipe, '12, leading into each i arch above the fuel, with suitable valves for i regulating the supply of air to the arch, 01 i excluding it altogether, and when fresh coal is added, or when the coal is stirred, I turn on ablast of air in the pipe leading into this upper part of the arch. This supplies air to the arch above the fire-bed and facilitates the burning of the products of combustion, which would otherwise be unconsumed. The attendant at the kiln may readily determine by operating the valves and by observing the effect when he has a sufficient amount of air for the best effect both in the arch above the fire-bed and in the ash-pit below the grate; but it will be understood that the additional supply of air above the fire-bed is to be used only when additional coal is supplied, or when the coal is stirred.

The effect of the water in the form of sp ay or steam is beneficial when wood is used, but in not so marked a degree as when it is applied to coal as a fuel.

I am well aware that it is not new in lime kilns to provide means for ejecting steam into thefurnace and ash-pits by means of a series of pipes leading from a boiler into flues, as in Letters Patent granted to A. Page, No. 227,872; further, that has also been described in the patent of Smith, No. 174,387; that liquid fuel is carried into the combustion-chamber by steam, and that air may be applied to the sides of or beneath the combust-ion-cl1amb'ers, and that this air may be con trolled by a blast, if desired. My invention as heretofore described is esentially different from the patents referred to, inasmuch as it consists of the combination of the blast beneath the grate for increasing the draft, and with a simultaneous application of a spray of water or jet of steam applied in front of or over the bed of coal in the fire-chamber, whereby overheating is prevented and the heat more evenly distributed to the stone in the barrel of the kiln.

I claim as my invention In combination with the barrel of the kiln and with the arch or fire-box thereof, having a grate, and with the ash-pit thereof, an air pipe communicating with the ash -pit be neath the grate, with air-forcing mechanism therefor, and a steam or water pipe arranged to discharge steam or water within the arch or fire-box and over the surface of the fuel, substantially as and for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GRANVILLE E. CARLETON.

\Yitnesses:

N. T. TALBOT, (l. I. RICHARDS.

IIO 

